Field of the Disclosure
This application generally relates to calibration of force sensors, and relates particularly to methods of self-calibrating force sensors and inertial compensation of force sensors.
Background of the Disclosure
Touch devices generally provide for identification of positions where the user touches the device, including movement, gestures, and other effects of position detection. For a first example, touch devices can provide information to a computing system regarding user interaction with a graphical user interface (GUI), such as pointing to elements, reorienting or repositioning those elements, editing or typing, and other GUI features. For a second example, touch devices can provide information to a computing system suitable for a user to interact with an application program, such as relating to input or manipulation of animation, photographs, pictures, slide presentations, sound, text, other audiovisual elements, and otherwise.
Some touch devices are able to determine a location of touch, or multiple locations for more than one touch, using sensing devices that are additional to those sensing devices already part of the touch device.
Generally, however, touch is binary. The touch is present and sensed, or it is not. This is true of many user inputs and input/output devices. A key of a keyboard, for example, is either pressed sufficiently to collapse a dome switch and generate an output signal, or it is not. A mouse button is either pressed sufficiently to close a switch, or it is not. Very few electronic devices employ force as a variable input.
The use of force sensors in personal electronic devices may allow for more complex, yet intuitive, input options between users and their devices. Additionally, these input options may open up new applications for personal electronics devices that incorporate force sensors.
Binary touch sensors may use a minimum level of force to register a touch. A force sensor, however, may register more information than just that the input surface has been touched; it may register a magnitude of the force behind that touch. Like all sensors, it may be useful to calibrate these force sensors to map the output signal of the force sensor to the magnitude of the force behind an input. Additionally, environmental factors, such as age, temperature, damage, or accelerations may affect the calibration of the force sensor.